The present invention relates generally to welding systems, and particularly to a welding system having a welding implement coupled to a source of electric power. In particular, one aspect of the present invention relates to a self-contained trigger and trigger lock assembly which may be incorporated into a welding implement
Welding is a method of joining pieces of metal together into one solid piece. Welding implements are used in a number of different types of welding. For example, welding implements are typically used in arc welding. An arc welding system typically comprises an electric power supply coupled to a welding implement that houses an electrode. The electric power supply typically includes a conductive cable and a clamp for securing the conductive cable to the metal piece to be welded. The electrode in the welding handle, along with the metal piece and conductive cable, completes an electrical circuit with the power supply when the electrode is placed against the metal piece. The contact between the electrode and the metal piece produces an electric arc between the electrode and the metal piece. The heat of the electric arc is concentrated on the metal piece, or pieces, to be joined. The heat of the arc causes the metal piece, or pieces, to melt. A filler material may be added to the molten metal. The molten mass cools and solidifies when the arc is removed, forming the weld.
MIG (Metal Inert Gas) welding is one type of arc welding. MIG welding is also referred to as “wire-feed” or GMAW (Gas Metal Arc Welding). In MIG welding, a metal wire is used as the electrode to produce the arc. The wire is shielded by an inert gas and the metal wire acts as the filler for the weld. The inert gas is used to shield the electric arc from outside contaminants and gases that may react with the weld. Non-inert gases, such as CO2, also are used in MIG welding. Typically, the wire and gas are fed through a hand-held welding implement. The wire and gas are fed to the welding implement from a welding system having a wire feeder, a power source, and a source of gas, such as a gas cylinder. The welding implement, typically, has a switch, or trigger, that is coupled to the rest of the system. When the trigger is operated, gas and wire are fed through the handle and power is applied to the wire. Typically, triggers have a spring that is used to bias the trigger to a disengaged position. The force of the spring must be overcome to operate the trigger.
Submerged arc welding is another type of arc welding method. In submerged arc welding, a wire feeder also is used to feed electrode wire through a welding implement. However, in submerged arc welding, a granular flux, rather than a gas, is used. In submerged arc welding, the point of metal fusion and the arc are submerged within the flux. The flux is a granular composition of chemical and metallic materials that shields the arc. The granular flux is continuously deposited by the welding implement just ahead of the electrode. The electrical current melts the electrode to form the weld puddle. The portion of the flux that is adjacent to the electrode tip and the puddle melts, forming a slag layer that refines the weld and excludes air. The wire and flux also are fed through a welding implement. The welding handle for a submerged arc welding system also, typically, has a switch, or trigger, that is coupled to a welding system. When the trigger is operated, the flux and the wire are fed through the welding implement and power is applied to the wire.
Trigger locks have been developed to maintain a trigger in an engaged position so that a user does not have to squeeze the trigger against spring force for an extended period of time. Currently, triggers and trigger locks are composed of numerous pieces that are adapted to cooperate with portions of the welding handle. For example, a typical trigger is used to operate a switch that is electrically coupled to the other components of the system, such as the power source. The switch is fixed in place in the handle and the trigger is fixed to the handle so that it can pivot relative to the handle to operate the switch. A typical trigger lock may have a stem, such as a pin, that extends through the trigger into a portion of the handle to maintain the trigger pivoted.
Assembling the trigger and trigger lock pieces together with the handle may be time-consuming. For example, to assemble the welding implement, the trigger and stem must be positioned in the welding handle so that the locking stem will be able to align with the hole in the welding handle. In addition, supplies of each of the parts must be maintained at the assembly area during assembly. Additionally, all of the parts must be tracked during disassembly to prevent a part from being lost. Additionally, the more the various individual pieces are required to cooperate, the greater the possibility of failure of the trigger and trigger lock.
There exists then a need for a welding system that utilizes a welding implement having fewer pieces for assembly. Additionally, there is a need for a trigger and trigger lock that has all of the components contained in a single device and which does not need to cooperate with portions of a welding handle to lock the trigger in a desired position.